Open barrel terminals, crimped to the end of an insulated conductor, have been known for use in electric wiring systems such as wire harnesses. Referring to FIG. 13, which is a schematic perspective view, open barrel crimp terminal 2 has wire barrel 21, which is to be crimped to wire end 41A of conductor 4, and insulation barrel 22, which is to be crimped to insulation end 41B. It comprises common barrel 21A of substantially semi-circular cross-section and a pair of wire claws 21C projecting therefrom. With wire end 4 1A and insulation end 42 accommodated in wire barrel 21 and insulation barrel 22, respectively, wire claws 21C and insulation claws 22C are crimped to a predetermined shape, thereby fixing crimp terminal 2 to conductor 4.
Referring to FIG. 14, which is a schematic section of a conventional terminal crimping apparatus, and FIG. 15, which is an enlarged view of its essential part, the prior art device, as disclosed for example in Japanese Patent Laid-open Publication No. 104577/1986, comprises anvil A fixed to frame 71, crimper C for crimping terminal 2 in cooperation with anvil A, sliding member 72 for driving crimper C toward and away from anvil A, and carrying hand 73 for carrying conductor 4. In the crimping process, common barrel 21A of terminal 2 is placed on anvil A in advance, and conductor end 41 with exposed wire end 41A is inserted into barrel 21A by carrying hand 73. Thereafter, wire claws 21C and insulation claws 22C of terminal 2 are crimped by crimper C, by which wire barrel 21 is fixed to wire end 41A and insulation barrel 22 is fixed to insulation end 41B.
What has been required in recent years in the terminal crimping apparatus as described above is to carry insulated conductor 4 automatically to terminal 2 on anvil A and to have anvil A and crimper C carry out a reliable crimping operation. However, according to the conventional devices, complete elimination of crimping defects has not been possible.
For example, conventional carrying hand 73 only supports the intermediate part of conductor 4 when it carries wire end 41A to crimped terminal 2; thus, if wire end 41A has been bent or torn, loose end 407 may be excluded from crimped terminal 2. This is caused by displacement of crimp terminal 2 on anvil A from the desired supply receiving position. Further, before crimping, wire claws 21C are spread toward crimper C at a predetermined angle. However, as shown in FIGS. 13 and 14, even slight deformation of claws 21C, excludes loose wire end 407. Also, a crimping defect occurs when crimp terminal 2 rolls during the crimping process. In such a case, as shown in FIG. 16, claws 21C and 22C butt against the recess of crimper C (see FIG. 16 (B)), thereby making it impossible to reliably crimp claws 21C and 22C.
Owing to a large number of causes, crimping defects are likely to occur. This has been a bottleneck for automation; especially in the case of crimping this type of terminal accommodated in a connector housing to an insulated conductor. The range in which the covered conductor 4 can be clamped is extremely restricted, so that failures as described above occur.